Recent tragedies at the Sago Mine, the Aracoma Alma Mine No. 1, and the Darby Mine No. 1 have focused renewed attention on an old problem: situational awareness in mine emergencies. Improved communication is a partial, but not complete, solution to the problem. Mine emergencies often involve dense smoke and dust that impair visibility and disorient even those familiar with the mine layout. And miners overcome by carbon monoxide cannot communicate useful information to potential rescuers. Location awareness is an important aspect of the overall problem of situational awareness. In too many cases, mine fatalities might have been avoided if rescuers knew the location of trapped or disabled miners. The more quickly a rescue team can reach miners at risk, the more likely the rescue operation will be successful. Currently, there is no technology capable of determining the precise location of underground miners with reasonable accuracy and cost. The principal benefit of the proposed effort lies in bringing to fruition a technology that can provide critically needed location information and thus aid in rescuing miners in emergency situations. Q-Track is the pioneer in Near-Field Electromagnetic Ranging or "NFER(R)" technology. NFER(R) systems operate in the MF band under Part 15 limits as low-power unlicensed transmitters. By using relatively low frequency, long wavelength transmissions, NFER(R) signals can propagate in complicated industrial environments with minimal impact from multipath. Furthermore, because these systems operate in the near-field zone, they have available much more tracking information than comparable high frequency or microwave systems. The specific aim of the Phase II effort is to develop prototype NFER(R) systems for wireless location in mines. The anticipated outcome of the proposed Phase II effort will be a prototype miner tracking system with the following characteristics: Range: >400m Accuracy: 10m or better Support for integration of sensors and transmission of low data rate telemetry. Public Health Relevance: Miners are not the only workers in dangerous environments who would benefit from location information. Soldiers, nuclear and chemical workers, and emergency responders all face comparable dangers and would all be helped by the availability of location data. By sponsoring the proposed effort, NIOSH will not only promote miner safety but also promote worker safety in a wide variety of secondary industries.